Refrigeration



Sept. 12, 1939. I w. R. HAINSWORTH 2,172,953

r REFRIGERATION I Filed Jui 21, 1937 2 Sheets-Sheet 1 INV ENT OR. 1

XT roRNEx my R M Sept. 12, 1939; w. R. HAINSWORTH I 2,172,958 a REFRIGERATION Filed July 21, 1957 2 Sheets-Sheet 2 3' I Y Z'ITOkNEY.

' 1 ENTOR. 32 Wdhm Km w/M Patented Sept. 1 2, 1 939.

UNITED STATES PATENT OFFICE .William R. Hainsworth, Larohmont, N. Y., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application July 21, 1937, Serial No. 154,748

12 Claims.

My invention relates to refrigeration, and-more particularly to humidity control of air in a storage compartment of a refrigerator.-

'It is an object of my invention to provide an improvement for cooling a storage compartment of a refrigerator whereby the humidity of air may be effectively controlled between relatively wide limits ranging from a comparatively low humidity to a comparatively high humidity,

I accomplish this by providing in a refrigerator storage compartment a low temperature cooling element which may be operated below the freez-. ing'temperature of water and a higher temperature cooling element which may be operatedabove the freezing temperature of water. The low and higher* temperature cooling elements are both provided with an extensive heat transfer surface whereby each element alone is capable of maintaining air in the storage compartment at a desired low temperature. By directing the flowof air over the surfaces of the low temperature or higher temperature cooling element, or varying the proportion of air flowing over the surfaces of both the cooling elements, the humidity of the storage compartment may be efiectively controlled. p 7

The invention, together, with the above and other objects and advantages thereof, will be more fully understood from the following description and accompanying drawings forming a part of this specification, and of which Fig. 1 is a front view of a storage compartment of a refrigerator embodying my invention; Fig. 2 is an' enlarged fragmentarysectional view taken on line 2- -2 of Figs. 1 and 3 to illustrate pcrts'of the apparatus more clearly; Fig. 3 is a sectional view taken on line 3-3 of Fig. 2; and Fig. 4 is a sectional view taken on line 4-4 of Fig. 3. ,1

Referring to Figs. 1 and 2, I have shown my invention embodied in a refrigerator comprising a cabinet l0 having an inner metal shell H arranged to be supported within an outer. metal shell I! and insulated therefrom with any suitable insulating material ll. The inner metal shell ll defines a thermally insulated storage compartment I! into whichaccess may be had by a; door i6 hinged to the front of the cabinet. The storage compartment Ii is provided with a plurality of shelves II for supporting food'products which are preserved and maintained at a desired low temperature by a coolingunlt or evaporator l8.

Thecooling unit ll,.as shown inl'igs. 2 to 4 inelusive, includes two upper coil; is connected by a cross conduit 20 and a lower coil 2! which is connected by a conduit 22 in'series relation with the upper coils IS. The upper coils iii are provided with a plurality of heat transferflns 23 and the lower coil 2i may be embedded in or otherwise suitably arranged in heat transfer re:- lation with a shell 24. The shell 24 is provided with a plurality of compartments to receive trays 25 for freezing water and the like.

The cooling unit l8 may form part of a refrigeration system of a uniform pressure absorption typ generally as described in Patent No. 1,609,334 to von Platen and Munters. .In a system of this type a refrigerant fluid, such-as ammonia, is introduced into the cooling unit. The refrigerant evaporates in the cooling unit and diffuses into an inert pressure equalizing gas, such as hydrogen,.to produce a refrigerating eflect. The. resulting gas mixture of refrigerant and inert gas flows from the cooling unit to an absorber in which the refrigerant gas is absorbed by a suitable liquid absorbent, such asxwater; The inert gas is returned to the cooling unit, and the enriched absorption liquid is conducted to a generator. By heating the generator the refrigerant is expelled from the absorption liquid, condensed in a suitable condenser, and then returned to the cooling unit to complete the refrigerating cycle. The weakened absorption liquid from which refrigerant has been expelled 'is conducted from the generator to the absorber to absorb refrigerant gas.

As shown in Figs. 2 to 4 inclusive, liquid refrigerant enters theleft-hand upper coil is through a conduit 26 and flows downward through both of the upper coils i8 and then through the lower coil 2|. The liquid refrigerant flows downward in coils I9 and 2| in counter-flow. to inert gas which flows upward and enters the lower coil 2| through conduit 21.. The refrigerant evaporates Y and diffuses into the inert gas, and the gas mixture of refrigerant and inert gas leaves the left.- hand upper coil through conduit 28.

Since the inert gas flows first through the lower coil 2| and then through the upper coils I 9-, the

gas in the upper coils. I! contains a. greater In accordance with iny invehtion, in order to control the humidity in storage compartment II between relatively wide limits, I provide the cooling unit I. with a 29.. The casing 29 includes horizontal baiiies 30 located below the cooling fins 23 of the upper coils i3, vertical bailles 3| extending downward from bailles 38 and on each side of shell 24, and a bottom baiiie 32 connecting the lower ends of vertical baiiles 3|. The baflies 30, 3|, and 32 may be fabricated from a single sheet of metal and supported in any suitable manner in storage compartment l5.

The casing 29 is closed at the front by a bafiie 33 having a door 34, as shown in Fig. 1, to provide access into the freezing compartments of shell 24. The casing 28 extends below the shell 24 to permit the insertion of a defrosting pan 35 below the low temperature cooling element. The pan 35 is provided with a cover-plate 36 which is flush with the front baflie 33 when the pan is positioned in casing 29.

The horizontal baiiles 30 are each provided with slots 31 and 38 which extend from the front baiiie 33 to the rear wall of the storage compartment I5, as shown most clearly in Fig. 4. The slots 31 are adjacent to the lateral side walls. of the storage compartment and the slots 38 are adjacent to the vertical bailles 3|. The vertical bailles 3| are also provided with slots 38 and similar to the slots in the horizontal bailies 33. The slots 38 are adjacent to the horizontal baffles 30 and the slots 40 are adjacent to the lower part of shell 24.

To control the flow of air over the surfaces of the low and higher temperature cooling elements, the slots 31 and 38 are provided with horizontal slides or shutters 4| and the slots 39 and 43 are provided with vertical slides or shutters 42. The slots may be flanged, as shown most clearly in Fig. 3, and the shutters 4| and 42 maybe arranged to move over the flanged edges of the slots or openings.

The shutters 4| and 42 may be manually controlled by a control knob 43 located at the upper part of the front baflie 33. The shutters 4| and 42 are preferably controlled simultaneously by the knob 43 and are so arranged that when the slots 31 and 39 are fully closed, the slots 38 and 40 are fully opened, as shown in Fig. 3; and, conversely, when the slots 31 and 33 are fully opened, the slots 38 and 40 are fully closed. This may be accomplished by a cable and pulley system including a shaft 44 to which the control knob 43 is secured. The shaft 44 is journaled in an opening in the front baiile 33 and an opening in a vertical bracket 45 which is of the general shape shown in Fig. 3 and secured, as by welding, for example, to the bailles 38 and 3|.

To the shaft 44 adjacent the bracket 45 is secured a double-grooved pulley 43. About each groove of pulley 46 is wound a wire or cable 41 whirh is connected to a horizontal shutter 4| and a vertical shutter 42. The cable 41 wound about the forward groove of pulley 43, for example, is operatively connected to the left-hand shutters 4| and 42. One part of the cable 41 which extends from the lower part of pulley 46 is connected at 43 to the inner edge of the left-hand shutter 4|. The other part of the cable extending from the upper part of pulley 46 bears against a small guide pulley 43 which is iournaled on a stub shaft 53 secured to bracket 45; From the guide pulley 48 the cable 41 extends downward and is secured at 5| to the upper edge of the left-hand vertical shutter 42.- The cable 41 wound about the rear groove of pulley 46 is connected in a similar manner to the right-hand shutters 4| and 42.

The shutters 4| and 42 are urged outward and downward by coil springs 52 and 53, respectively, which cooperate with the cable and pulley system just described to permit adjustment of the The operating temperatures of the low and higher temperature coils 2| and i9, respectively, may be controlled by suitable mechanism including a control knob 54 located at the upper part of front baille 33. Referring to Fig. 2, the control knob 54 may be fixed to a rod 55 that extends rearwardly through the i'earwall of the storage compartment I5. To the rod 55 is secured a grooved pulley 56 which is operatively connected by a flexible wire belt 51 to suitable mechanism (not shown) for controlling the energy supply to the refrigeration apparatus and hence the operating temperatures of the low and higher temperature cooling coils 2| and Hi. The control knob 54 is provided with an indicator 54' and-may also be arranged to initiate defrosting as well "as control he operating temperatures of the coils l8 and 2|. Control mechanism of this character is fully described and illustrated in United States Patent No. 2,123,921 to Andersson.

The parts of the control mechanism illustrated and just described are similar to parts shown in the above-mentioned Andersson application. The control mechanism is provided with an expansible fluid thermostat for maintaining the cooling elements at a substantially constant temperature. The expansible fluid thermostat includes a thermal element (not shown) which is connected by a capillary tube 58 to a thermal bulb 58 arranged in heat exchange relation with the shell 24, as shown in Fig. 3. The operation of the apparatus just described to effect humidity control in storage compartment i5 is substantially as follows: When it is desired to maintain the storage compartment at the lowest humidity, the control knob 43 is moved to such a position on indicator 43' that the shutt'ers 4| and 42 will assume the positions shown in Fig. 3. With the slots 31 and 39 fully closed and the slots 38 and 40 fully opened, air cooled by thermal transfer with the shell 24 flows through slots 48 and downward in the compartment to replace warmer air which flows upward and passes through the slots 38. This natural circulation of air in the storage compartment, which is indicated by the arrows in Fig. 3, is due to the difference in specific weights of air at different temperatures. With the slots 38 and 40 fully opened, therefore, air flows in thermal transfer relation with the shell 24 in. which the coil 2| is embedded. Since the coil 2| and shell 24 constitute the low temperature cooling element which is being operated below the freezing temperature of water, water vapor is condensed out of the air flowing over the surfaces of shell 24. The water vapor condensed in this manner freezes and forms a coating of frost on shell 24. Under these conditions the greatest amount of water vapor is removed from the air and the humidity in the storage compartment is is comparatively low.

Since cooling of air in the compartment is effected by the low temperature cooling element when a comparatively low humidity is desired,

knob 4; is moved to such a position on indicator 43' that the shutters I and 42 will fully close the slots 38 and 40 and fully open-the slots 31 15 and 39. With slots 31 and 38 fully open, air cooled by thermal transfer with the upper coils i9 and fins 23 flows through slots 39 an downward in the compartment to replace we in air flowing upward and passing through slots 31.

20 Since the coils i9 and cooling fins 23 constitute the higher temperature cooling element which a is being operated above the-freezing temperature of water, less water vapor is condensed out of air flowing in thermal contact with these parts. When the relative humidity of the air in the compartment is below a definite value, no water vapor is removed from the air because of the higheroperating temperature of the upper coils it.

Under these conditions the least amount of water 3w vapor is removed from the air and the humidity is the storage compartment is comparatively The control knob 43 may be moved to any positlon on the indicator 63' between the two posi- 3 tlOns just described to maintain the humidity of the compartment at an intermediate value. .In-such case all of the slots 37, 38, t9, and it are partially opened, and the extent to which air is permitted to pass through the difierent slots may 49 be varied atwill. 7

With the slots 31 and 38 both partially opened, a portion oi the air flowing upward in the coinpartment will pass through slots El and flow in thermal transfer relation with the upper coils 45 it and cooling fins 23, and the remaining portion will pass through slots 33 and not be cooled to any great extent by the upper coils and fins. Similarly, with the slots 39 and M both partially openeda portion of the air will pass through the upper slots so and not be cooled to any great extent by the shell, and the remaining portion will flow in thermal contact with the shell and pass through the lower slots 40. By controlling the extent to'which the shutters M and 4t,

partially close the different slots, therefore, the

relative amount of air flowing over both the low a and higher temperature cooling elements may be variedto maintain the storage compartment at any desired humidity. Y I up The indicators? may be graduated in any suitable manner to indicate the varying degrees of humidity that may be obtained. Instead of manually controlling the humidity of air, automatic control may be easily effected by providing.

5 a humidostat in the compartment which is in- A- financed by the humidity of air. Such humidostat may be operatively connected to the mechani'sm controlling movement of the shutters to reg- :ulate the flow of air in contact with the low and 70 higher temperature cooling elements.

By controlling the flow of air in the storage compartment so that all or only a portion of the air flows over the surfaces of each cooling element, the humidity may be varied over a relays tively wide range depending upon the diflerence i v 2,172,955 7 the coil 2| and shell 2i are of such size that an and range of operating temperatures of the low and higher temperature cooling elements. Further, controlling the flow of air in the manner described is selective in that the humidity of the compartment may be maintained at any value between the lowest and highest humidities that may be obtained in the compartment.

. The provision of controlling the humidity as well as the temperature of the storage compartment is of distinct advantage in that the humidity control may be varied when the temperature of the storage compartment is increased or decreased to effect substantially the same food preservation under diilerent operating conditions. Thus, when'the temperature of the storage compartment'is decreased, for example, the humidity may be increased; and, conversely, when the temperature of the storage compartment is increased, the humidity may be decreased. Stated another way, when the operating temperatures of the low and, higher. temperature cooling elements are both decreased to lower the temperature of the storage compartment, a greater amount 01' air may be permitted to circulate in thermal transfer relation with the higher temperature cooling element. Also, when the operating temperatures of the low and higher temperature cooling elements are both increased to increase the tem-- perature of the storage compartment, a greater amount of air may be permitted to circulate in thermal transfer relation with the low temperature cooling element.

While I have shown and described a particular embodiment of my invention, it will be apparent to those skilled in the art that modifications and changes may be made without departing from the spirit and scope of the invention. Thus, a

the natural circulation of air they be augmented by forced draft and the two cooling elements may be operated at temperatures different from those specified above. I therefore do not wish to be limited to the actual structure shown in the drawings and described in the specification and aim in the following claims to cover all modifications and changes which fall within the true spirit and scope of the invention.

What is'claimed is: v

1. In a refrigerator having a thermally insulated storage compartment, refrigeration apparatus including a low temperature cooling element and a higher temperature cooling element, said cooling elements being disposed in the upper part of said compartment for cooling air flowing in contact therewith, and means to control the proportion of air flowing in contactwith said low and. said higher temperature cooling elements and thereby regulate the humidity of air in said I compartment.

2. In a refrigerator having a thermally insulated storage compartment, refrigeration apparatus including a plurality of cooling elements adapted to be operated at different temperatures, said cooling elements being disposed in said compartment for cooling air flowing in contact therewith, and means to control'the extent of air cooling effected by each of said cooling elements. 1

3. Refrigeration apparatus including a low temperature cooling element and a higher temperature coolingelement for cooling air flowing in contact therewith, means operative to simultaneously increase or decrease the temperatures of said cooling elements, and structure con.- structed and arranged to control the extent of air cooling eflected by each of saidcooling elements.

4. A method of co trolling the humidity of air in a thermally insulated space which comprises producing a refrigerating effect at one region below the freezing temperature of water and a refrigerating eifect above the freezing temperature of water at asecond region, causing circulation of air in said space, and controlling the relative amounts of circulating air permitted to flow in each of said regions and thereby determine the amount of water vapor condensed out of the air due to said refrigerating effects.

-5. In a refrigerator having a thermally insulated storage space, refrigeration apparatus including a low temperature cooling element and ahigher temperature cooling element, said cooling elements being disposed in the upper part of said space with said higher temperature cooling element above said low temperature cooling element, said cooling elements being capable of cooling air circulating in said space and flowing in thermal transfer relation therewith, and means to by-pass air around at least, a part of said higher temperature cooling element for flow in thermal transfer relation with said low temperature cooling element. I

6. Refrigeration apparatus including .a low temperature cooling element and a higher temperature cooling element, said cooling elements being so constructed and arranged that substantially all of the air in a path of flow is always cooled by thermaltransfer therewith, means to increase or decrease the normal operating temperatures of said cooling elements, and means to control the relative amount of air in said path of flow which passes in thermal transfer relation with each of said cooling elements.

'7. Refrigeration apparatus including a plurality of cooling elements for cooling air flowing in contact therewith, said cooling elements being operated at different temperatures. means operative to simultaneously increase or decrease the temperatures of said cooling elements, and structure including a single control member operative to vary theproportion of air flowing "in thermal transfer relation with each of said elements.

, 8. A method of controlling humidity of air in a thermally insulated space in whicha refrigerating effect at one temperature is produced in one region and another refrigerating effect at a higher temperature is produced in a second region above said first region, which comprises causing air to circulate in said thermally insulated space, and controlling the relative amounts of circulating air flowing in each of said regions'to determine the amount of water vapor condensed out of the circulating air due to said refrigerating effects.

Y 9. In a refrigerator having a thermally insulated storage compartment, refrigeration apparatus including a 'cooling unit having a low temperature portion, a casing around said low temperature portion, means for controlling flow of air through said casing, said casing having openings for insertion of receptacles within said casing, closure members for said openings, and a 4 receptacle adapted to be inserted through one of said openings within said casing below said low temperature portion.

v1i). A refrigerator as set forth in claim 9 in which the front of said receptacle servesas one I of said closure membersfor said opening. 11. A method of preserving foods in a thermally insulated storage space which comprises producing refrigeration at two different temperatures; varying said temperatures at which re-' frigeration is produced, utilizing said refrigeration to cool air in said space, and changing the proportion of air cooling by refrigeration at one of said temperatures with respect to air cooling by refrigeration at another of said refrigeration temperatures .as said temperatures are varied.

12. Refrigeration apparatus including a high temperature cooling element and a low temperature coolingelement, means to flow liquid refrigerant through said cooling elements in series respectively, means for circulating inert gas through said cooling elements in series reversely, and means to control flow of air to be cooled in thermal transferrelation with each of said cool.- ing elements.

' WILLIAM R. HAINSWORTH. 

